Motor Unit Potentials Research Articles

Split hand and minipolymyoclonus in spinocerebellar ataxia type 3: a case report

BackgroundSpinocerebellar ataxia type 3 (SCA3), also known as Machado–Joseph disease, is an autosomal dominant neurodegenerative disorder caused by CAG repeat expansion in exon 10 of ATXN3. Extra-cerebellar manifestations, including external ophthalmoplegia, dystonia, Parkinsonism, and peripheral neuropathy, are predominantly present in SCA3 cases. Here, we report a case of SCA3 presenting with a split hand and minipolymyoclonus.Case presentationA 73-year-old female patient presented with a 5-year history of ataxic gait. Neurological examination revealed cerebellar ataxia and minipolymyoclonus in the digits on both sides and muscle atrophy in the right hand, consistent with the split hand pattern. Electrodiagnostic studies demonstrated decreased amplitude of compound muscle action potentials and neurogenic motor unit potentials, indicating lower motor neuron involvement.ConclusionsOur patient’s case indicated a split hand and minipolymyoclonus in SCA3. Clinicians should consider these extra-cerebellar manifestations in patients with SCA3. Although neither split hand nor minipolymyoclonus are likely to directly result in a specific etiological diagnosis, a common pathophysiological mechanism for both may be lower motor neuron involvement. This extracerebellar manifestation contributes to narrowing down the diagnostic possibilities for cases presenting with progressive cerebellar ataxia.

Lately Obtained Baseline Waves in Motor Evoked Potential Monitoring during the Surgery of Frontal Lobe Tumor

Intraoperative neurophysiologic monitoring during brain tumor surgery should acquire a baseline data as soon as possible. However, motor unit potentials (MEP) in our case showed baseline data could not be acquired in the early stage of surgery, but consecutive trials had abrupt appearance of MEP just after dura opening. This case shows the acquisition of baseline MEP during brain tumor surgery should not be given up until the dura is open especially in a state of raised intracranial pressure.

7654 Unusual Case of Lipodystrophy: A Novel Disease Phenotype?

Abstract Disclosure: M. Celik Guler: None. E.D. Frontera: None. K. Hoose: None. M.C. Foss de Freitas: Advisory Board Member; Self; PTC Therapeutics. Speaker; Self; Amryt. L. Douyon: None. E.A. Oral: Advisory Board Member; Self; Amryt, Regeneron Pharmaceuticals. Consulting Fee; Self; Regeneron Pharmaceuticals, Amryt, Third Rock Ventures. Grant Recipient; Self; Regeneron Pharmaceuticals, Amryt. Research Investigator; Self; Novo Nordisk, Ionis Pharmaceuticals Inc., Fractyl, GI Dynamics, Rhythm Pharmaceuticals. Other; Self; Amryt. Background: Lipodystrophy syndromes (LD) are rare disorders characterized by varying degrees of adipose tissue deficiency that can predispose individuals to severe metabolic complications. Although these syndromes are traditionally subclassified based on inheritance patterns and the degree of adipose tissue loss, patients may exhibit highly heterogeneous clinical presentations. In this context, we report a unique case of partial lipodystrophy with an unusual distribution of adipose tissue that likely represents a novel syndrome and challenges conventional phenotypes. Clinical Case: A 60-year-old Puerto Rican female patient with medical history of type 1 diabetes mellitus (DM), obesity, hyperlipidemia, irritable bowel syndrome, asthma, and coronary artery disease was referred to us for unexplained asymmetric distribution of adipose tissue. She had chronic left posterolateral hip pain and lipoatrophy in her left lower extremity. Her medical history showed that she was born approximately 7 lbs., with no evidence of trauma during delivery. Her mother was given an unknown medication for improving circulation to the placenta. She had a morphea like rash on the arms and chest wall more prominent on the left upper body at birth. In addition, a dimple on her hip was noticed by her mother during the early stages of infancy. Despite the normal progression of neurological development (walking/climbing stairs), she always had a very mild limp. Also, her right arm was always 2 inches larger than her left arm. When she gained weight, she also put on more asymmetric weight on the left side of the abdomen and left lower torso. She had been treated with insulin injections since she was diagnosed with diabetes at the age of 11. She never demonstrated any islet cell specific antibodies. She had a normal weight until pregnancy at the age of 27, during which she gained 20 lbs. Her weight continued to increase over time, and the maximum was 212 lbs. Her examination reveals a BMI of 41.46 kg/m² with excess fat in the right arm, mid-section, left thigh, and left mons pubis. Conversely, only the left leg appears to demonstrate specific fat atrophy, with a near-total loss of adipose tissue starting from the mid-gluteal region. The hip MRI result reported moderate osteoarthritis of the left hip. EMG revealed signs of length-dependent sensorimotor axonal polyneuropathy and long duration/large amplitude motor unit potentials isolated only in the left medial gastrocnemius muscle. Triglyceride level was 73 mg/dL, HbA1c level was 6.8%, with an average total insulin dosage of around 43 IU/day. There was no history of pancreatitis due to hypertriglyceridemia. Conclusion: Our case highlights the heterogeneity of the lipodystrophy spectrum with a novel presentation of lipodystrophy. In addition, there may be homeostatic control of deposition of fat to seek symmetry between upper versus lower and right versus left sided depots. Presentation: 6/1/2024

The effects of exercise, heat-induced hypo-hydration and rehydration on blood-brain-barrier permeability, corticospinal and peripheral excitability.

The effects of low-intensity exercise, heat-induced hypo-hydration and rehydration on maximal strength and the underlying neurophysiological mechanisms are not well understood. To assess this, 12 participants took part in a randomised crossover study, in a prolonged (3h) submaximal (60W) cycling protocol under 3 conditions: (i) in 45°C (achieving ~ 5% body mass reduction), with post-exercise rehydration in 2h (RHY2), (ii) with rehydration across 24h (RHY24), and (iii) a euhydrated trial in 25°C (CON). Dependent variables included maximal voluntary contractions (MVC), maximum motor unit potential (MMAX), motor evoked potential (MEPRAW) amplitude and cortical silent period (cSP) duration. Blood-brain-barrier integrity was also assessed by serum Ubiquitin Carboxyl-terminal Hydrolase (UCH-L1) concentrations. All measures were obtained immediately pre, post, post 2h and 24h. During both dehydration trials, MVC (RHY2: p < 0.001, RHY24: p = 0.001) and MEPRAW (RHY2: p = 0.025, RHY24: p = 0.045) decreased from pre- to post-exercise. MEPRAW returned to baseline during RHY2 and CON, but not RHY24 (p = 0.020). MEP/MMAX ratio decreased across time for all trials (p = 0.009) and returned to baseline, except RHY24 (p < 0.026). Increased cSP (p = 0.011) was observed during CON post-exercise, but not during RHY2 and RHY24. Serum UCH-L1 increased across time for all conditions (p < 0.001) but was not significantly different between conditions. Our findings demonstrate an increase in corticospinal inhibition after exercise with fluid ingestion, but a decrease in corticospinal excitability after heat-induced hypo-hydration. In addition, low-intensity exercise increases peripheral markers of blood-brain-barrier permeability.Kindly check and confirm inserted city name correctly identified in affiliation 7This is correct.

Utility of the Clustering Index method for diagnosing neuromuscular disorders as compared with needle electromyography.

Concentric needle electromyography (CNEMG) is an essential examination for evaluating neuromuscular disorders, although pain is a drawback. Clustering Index (CI) method is a non-invasive quantitative analysis for surface electromyography (SEMG) that evaluates whether the signal area is clustered into the few large motor unit potentials (MUPs) or is evenly distributed. However, the diagnostic yield of the CI method in comparison with CNEMG is not known. In this study, we aimed to compare the sensitivity of the CI method with MUP parameters in CNEMG for diagnosing neurogenic or myogenic disorders. We retrospectively identified patients for whom both SEMG and CNEMG were performed on the same tibialis anterior (TA) muscle. In CNEMG, seven MUP parameters were evaluated, including size index (SI) and revised size indices for neurogenic (rSIn) and myogenic (rSIm) disorders. Identified were 21 patients with neurogenic and 21 patients with myogenic disorders. Control data were constructed from 30 control subjects. The sensitivities of the CI method for the neurogenic and myogenic groups were 76% and 62%, respectively, which were not significantly different from MUP parameters, except for being significantly higher than those of amplitude and duration for myopathy (24%). Among MUP parameters, the sensitivities of rSIn (62%) and rSIm (57%) for myopathy were significantly higher than those of amplitude and duration. The CI method significantly correlated with the strength of the TA muscle in myopathy. The CI method, having comparable diagnostic yields to MUP parameters, is promising as a non-invasive diagnostic measure.

Influence of nitrate supplementation on motor unit activity during recovery following a sustained ischemic contraction in recreationally active young males

PurposeDietary nitrate (NO3−) supplementation enhances muscle blood flow and metabolic efficiency in hypoxia, however, its efficacy on neuromuscular function and specifically, the effect on motor unit (MU) activity is less clear. We investigated whether NO3− supplementation affected MU activity following a 3 min sustained ischemic contraction and whether this is influenced by blood flow restriction (BFR) during the recovery period.MethodIn a randomized, double-blinded, cross-over design, 14 males (mean ± SD, 25 ± 6 years) completed two trials following 5 days of supplementation with NO3−-rich (NIT) or NO3−-depleted (PLA) beetroot juice to modify plasma nitrite (NO2−) concentration (482 ± 92 vs. 198 ± 48 nmol·L−1, p < 0.001). Intramuscular electromyography was used to assess MU potential (MUP) size (duration and area) and mean firing rates (MUFR) during a 3 min submaximal (25% MVC) isometric contraction with BFR. These variables were also assessed during a 90 s recovery period with the first half completed with, and the second half completed without, BFR.ResultsThe change in MUP area and MUFR, did not differ between conditions (all p > 0.05), but NIT elicited a reduction in MUP recovery time during brief isometric contractions (p < 0.001), and during recoveries with (p = 0.002) and without (p = 0.012) BFR.ConclusionThese novel observations improve understanding of the effects of NO3− on the recovery of neuromuscular function post-exercise and might have implications for recovery of muscle contractile function.Trial registrationThe study was registered on clinicaltrials.gov with ID of NCT05993715 on August 08, 2023.

Quantitative evaluation of factors influencing the 3 Hz repetitive nerve stimulation test in patients with amyotrophic lateral sclerosis.

Previous studies have suggested that treatments targeting the neuromuscular junction (NMJ) may play a role in the treatment of amyotrophic lateral sclerosis (ALS). However, factors impacting repetitive nerve stimulation (RNS), a technique to evaluate NMJ function, have yet to be fully elucidated. We aimed to identify independent factors contributing to the decremental response of the accessory nerve and evaluated its value in ALS clinical practice. A total of 626 patients who were diagnosed with ALS and underwent 3 Hz RNS tests on the accessory nerve were enrolled. Data on their clinical and electrophysiological indicators were divided into a training set (collected from June 2016 to December 2022) and a test set (collected from January to August 2023). Stepwise regression was used in independent variable selection and model building. Forty-two percent of patients had a decrement larger than 10% and 24% had a decrement larger than 15%. Onset age, sex, onset site, forced vital capacity (FVC) and motor unit potential (MUP) duration were independent factors contributing to the results of the RNS test. MUP duration had the greatest impact on decremental response, followed by FVC and onset age. The decremental response in females was larger than in males. Upper limb onset was found to contribute more to the decrement than lower limb or bulbar onset. In patients with ALS, NMJ safety factor is reduced during re-innervation. Decremental response is affected by multiple factors, which needs to be considered in clinical trials targeting the NMJ in these patients.

Assessing Rat Diaphragm Motor Unit Connectivity Outcome Measures as Quantitative Biomarkers of Phrenic Motor Neuron Degeneration and Compensation.

Loss of ventilatory muscle function is a consequence of motor neuron injury and neurodegeneration (e.g., cervical spinal cord injury and amyotrophic lateral sclerosis, respectively). Phrenic motor neurons are the final link between the central nervous system and muscle, and their respective motor units (groups of muscle fibers innervated by a single motor neuron) represent the smallest functional unit of the neuromuscular ventilatory system. Compound muscle action potential (CMAP), single motor unit potential (SMUP), and motor unit number estimation (MUNE) are established electrophysiological approaches that enable the longitudinal assessment of motor unit integrity in animal models over time but have mostly been applied to limb muscles. Therefore, the objectives of this study are to describe an approach in preclinical rodent studies that can be used longitudinally to quantify the phrenic MUNE, motor unit size (represented as SMUP), and CMAP, and then to demonstrate the utility of these approaches in a motor neuron loss model. Sensitive, objective, and translationally relevant biomarkers for neuronal injury, degeneration, and regeneration in motor neuron injury and diseases can significantly aid and accelerate experimental research discoveries to clinical testing.

Diaphragm weakness in late-onset Pompe disease: A complex interplay between lower motor neuron and muscle fibre degeneration

BackgroundLate-onset Pompe disease (LOPD) patients may still need ventilation support at some point of their disease course, despite regular recombinant human alglucosidase alfa treatment. This suggest that other pathophysiological mechanisms than muscle fibre lesion can contribute to the respiratory failure process. We investigate through neurophysiology whether spinal phrenic motor neuron dysfunction could contribute to diaphragm weakness in LOPD patients. Material and methodsA group of symptomatic LOPD patients were prospectively studied in our centre from January 2022 to April 2023. We collected both demographic and clinical data, as well as neurophysiological parameters. Phrenic nerve conduction studies and needle EMG sampling of the diaphragm were perfomed. ResultsEight treated LOPD patients (3 males, 37.5%) were investigated. Three patients (37.5%) with no respiratory involvement had normal phrenic nerve motor responses [median phrenic compound muscle action potential (CMAP) amplitude of 0.49 mV; 1st-3rd interquartile range (IQR), 0.48–0.65]. Those with respiratory failure (under nocturnal non-invasive ventilation) had abnormal phrenic nerve motor responses (median phrenic CMAP amplitude of 0 mV; 1st-3rd IQR, 0–0.15), and were then investigated with EMG. Diaphragm needle EMG revealed both myopathic and neurogenic changes in 3 (60%) and myopathic potentials in 1 patient. In the last one, no motor unit potentials could be recruited. ConclusionsOur study provide new insights regarding respiratory mechanisms in LOPD, suggesting a contribution of spinal phrenic motor neuron dysfunction for diaphragm weakness. If confirmed in further studies, our results recommend the need of new drugs crossing the blood-brain barrier.

Hemimasticatory spasm: a series of 17 cases and a comprehensive review of the literature.

Hemimasticatory spasm (HMS) is a rare movement disorder characterized by paroxysmal spasms or twitches of the unilateral jaw-closing muscles. This study aimed to comprehensively evaluate the clinical features of patients with HMS. Data from 17 patients newly diagnosed with HMS (12 females and 5 males; mean age at onset: 46.7 years) who visited our department were retrospectively analyzed, and a literature search based on electronic medical databases from their inception until November 30, 2023, was conducted. A manual search was conducted for articles cited in the related literature. A total of 117 cases (72 females and 45 males; mean age at onset: 37.1 years) from 57 studies were analyzed. The muscles involved were the masseter (97.4%), temporalis (47.9%), and medial pterygoid (6%). Morphea or scleroderma was observed in 23.9% of the patients, and facial hemiatrophy in 27.4%. In 17.9% of the cases, Parry-Romberg syndrome was either complicated or suspected. Typical electromyographic findings included the absence of a silent period during spasms (23.9%) and irregular brief bursts of multiple motor unit potentials. Oral medicines, such as clonazepam or carbamazepine, alleviated the symptoms for some patients but were often unsatisfactory. Botulinum toxin therapy was effective in most cases. Recently, microvascular decompression surgery is increasingly being used, resulting in complete relief in some cases. In conclusion, highly effective modalities are currently available, and it is necessary to raise awareness of HMS to ensure that it can be diagnosed and treated accurately by both medical and dental professionals.

Bruns Garland Syndrome as the first presentation of type 2 diabetes: two case reports and a practical approach to diagnosis

BackgroundDiabetes is a global health problem causing a significant burden on the healthcare systems both due to the disease itself and associated complications. Diabetic radiculoplexus neuropathies or Bruns–Garland syndrome constitutes a rare form of microvascular complications, more commonly affecting the lumbosacral plexus and, very rarely, the cervical plexus. We describe two Sri Lankan males who presented with diabetic lumbosacral radiculoplexus neuropathy and diabetic cervical radiculoplexus neuropathy as the initial manifestation of diabetes.Case descriptionCase 1: a 49-year-old Sri Lankan hotel chef presented with subacute painful weakness and wasting of the left upper arm for 3 months and weight loss. Left upper limb proximal muscles were wasted with diminished power and reflexes. A nerve conduction study showed comparative amplitude reduction. An electromyogram revealed positive sharp waves, frequent fibrillations, and high amplitude polyphasic motor unit potentials with reduced recruitment in proximal muscles of left upper limb. Case-2: a 47-year-old Sri Lankan carpenter presented with subacute progressive asymmetrical painful weakness and wasting of bilateral thighs for 5 months and weight loss. Lower limb proximal muscles were wasted with reduced power and knee jerks. The nerve conduction study was normal. The electromyogram was similar to case 1 involving both quadratus femoris muscles, which was more prominent on the left side. The work up for an underlying etiology revealed only elevated fasting blood glucose and HbA1c, suggesting a new diagnosis of diabetes associated with neurological symptoms. Patient 1 was diagnosed with diabetic cervical radiculoplexus neuropathy and patient 2 with diabetic lumbosacral radiculoplexus neuropathy. Both showed significant improvement following optimization of glycemic control together with symptomatic treatment and physiotherapy.ConclusionDiagnosis of diabetic radiculoplexus neuropathy requires a comprehensive workup to rule out other sinister pathologies. This case report has a dual importance; it describes diabetic radiculoplexus neuropathy as the very first manifestation of two previously healthy people, giving rise to a new diagnosis of diabetes and, at the same time, reporting on diabetic cervical radiculoplexus neuropathy, which is extremely rare and has never been previously reported in Sri Lanka.

Understanding EMG PDF Changes With Motor Unit Potential Amplitudes, Firing Rates, and Noise Level Through EMG Filling Curve Analysis.

EMG filling curve characterizes the EMG filling process and EMG probability density function (PDF) shape change for the entire force range of a muscle. We aim to understand the relation between the physiological and recording variables, and the resulting EMG filling curves. We thereby present an analytical and simulation study to explain how the filling curve patterns relate to specific changes in the motor unit potential (MUP) waveforms and motor unit (MU) firing rates, the two main factors affecting the EMG PDF, but also to recording conditions in terms of noise level. We compare the analytical results with simulated cases verifying a perfect agreement with the analytical model. Finally, we present a set of real EMG filling curves with distinct patterns to explain the information about MUP amplitudes, MU firing rates, and noise level that these patterns provide in the light of the analytical study. Our findings reflect that the filling factor increases when firing rate increases or when newly recruited motor unit have potentials of smaller or equal amplitude than the former ones. On the other hand, the filling factor decreases when newly recruited potentials are larger in amplitude than the previous potentials. Filling curves are shown to be consistent under changes of the MUP waveform, and stretched under MUP amplitude scaling. Our findings also show how additive noise affects the filling curve and can even impede to obtain reliable information from the EMG PDF statistics.

Electrophysiological diagnostics in choosing treatment strategy for neuropathies in children with transcondylar fractures

A common complication of transcondylar fractures (TCF) in children is neuropathy requiring not only therapeutic but also surgical treatment. Despite numerous reports, clear criteria for selecting patients for surgical treatment have not been defined. To clarify the role of clinical and electrophysiological diagnostics in choosing treatment tactics for neuropathies in children with TCF. There were 20 patients with neuropathies after TCF between 2020 and 2022. Of these, 10 ones were selected for surgical treatment according to electrophysiological diagnostic data. Inclusion criteria: age 6-12 years, closed TCF within previous 3-12 months, symptoms of neuropathy confirmed by electroneuromyography (ENMG), no nerve disruption according to ultrasound data. Exclusion criteria: elbow joint contracture and post-traumatic ulnar nerve dislocation. All patients underwent needle myography with functional assessment of motor and sensory fibers, spontaneous activity in muscles, recruitment pattern and motor unit potentials. Intraoperative electrophysiological diagnostics included stimulation of motor fascicles with registration of M-responses from the target muscles. The follow-up period was 3-6 months. The study included 20 patients aged 6-12 years without peripheral nerve disruption. A group of 10 patients who required surgical treatment was identified. The control group consisted of 10 patients who did not require surgical treatment. To choose treatment tactics, we considered ENMG data. Surgical procedure was determined according to intraoperative neuromonitoring (IONM) data. When choosing treatment strategy, surgeons should consider objective ENMG and IONM criteria, as well as fascicular anatomy.

Assessment of Motor Unit Potentials Duration as the Biomarker of DT-DEC01 Cell Therapy Efficacy in Duchenne Muscular Dystrophy Patients up to 12 Months After Systemic–Intraosseous Administration

Duchenne muscular dystrophy (DMD) is a lethal X-linked disease caused by mutations in the dystrophin gene, leading to muscle degeneration and wasting. Electromyography (EMG) is an objective electrophysiological biomarker of muscle fiber function in muscular dystrophies. A novel, DT-DEC01 therapy, consisting of Dystrophin Expressing Chimeric (DEC) cells created by fusing allogeneic myoblasts from normal donors with autologous myoblasts from DMD-affected patients, was assessed for safety and preliminary efficacy in boys of age 6–15 years old (n = 3). Assessments included EMG testing of selected muscles of upper (deltoideus, biceps brachii) and lower (rectus femoris and gastrocnemius) extremities at the screening visit and at 3, 6, and 12 months following systemic–intraosseous administration of a single low dose of DT-DEC01 therapy (Bioethics Committee approval no. 46/2019). No immunosuppression was administered. Safety of DT-DEC01 was confirmed by the lack of therapy-related Adverse Events or Serious Adverse Events up to 22 months following DT-DEC01 administration. EMG of selected muscles of both, ambulatory and non-ambulatory patients confirmed preliminary efficacy of DT-DEC01 therapy by an increase in motor unit potentials (MUP) duration, amplitudes, and polyphasic MUPs at 12 months. This study confirmed EMG as a reliable and objective biomarker of functional assessment in DMD patients after intraosseous administration of the novel DT-DEC01 therapy.

Myelin abnormalities in merosin-deficient congenital muscular dystrophy.

Merosin is a protein complex located in the basement membrane of skeletal muscles and laminin α2-containing regions of the central and peripheral nervous systems. However, because of the prominence of muscle-related symptoms, peripheral neuropathy associated with merosin-deficient congenital muscular dystrophy type 1A (MDC1A) has received little clinical attention. This study aimed to present pathological changes in intramuscular nerves of three patients with MDC1A and discuss their relationship with electrophysiological findings to provide new evidence of peripheral nerve involvement in MDC1A. MDC1A was confirmed by clinical features, muscle biopsy, and genetic testing for variants in LAMA2. To clarify peripheral nerve involvement, we statistically evaluated electrophysiological and muscle pathology findings of intramuscular nerves. These findings were compared with those of age-matched boys with Duchenne muscular dystrophy (DMD) as controls with normal nerves. Nerve conduction studies (NCS) were performed before biopsy. Biopsied intramuscular nerves were examined with electron microscopy using g-ratio, which is the ratio of axon diameter to myelinated fiber diameter. The myelin sheaths were significantly thinner in MDC1A patients than in age-matched DMD patients, with a mean g-ratio of 0.76 ± 0.07 in MDC1A patients and 0.65 ± 0.14 in DMD patients (p < .0001). No neuropathic changes were identified in muscle pathology. Low compound muscle action potential amplitudes, positive sharp waves and fibrillation potentials, and low-amplitude motor unit potentials with increased polyphasia indicated myopathic changes; no neurogenic changes were seen. We postulate that the thin myelin associated with MDC1A reflects the role of merosin in myelin maturation.

Changes in electrophysiological findings of spinal muscular atrophy type I after the administration of nusinersen and onasemnogene abeparvovec: two case reports

BackgroundRecently, there have been significant advances in the treatment of spinal muscular atrophy (SMA). Although clinical improvement in patients with SMA after the treatment has been reported, changes in electrophysiological findings, especially needle electromyography (EMG), have rarely been reported. Herein, we report the posttreatment changes in EMG and nerve conduction study findings over time in two patients with SMA type I.Case presentationPatient 1: A 2.5-year-old girl was diagnosed with SMA type I at 1 month of age. She received nusinersen four times and onasemnogene abeparvovec (OA) was administered at 6 months of age. The compound muscle action potential (CMAP) amplitudes of the median and tibial nerves increased over time. The needle EMG after the treatment showed high-amplitude motor unit potentials (MUPs) suggestive of reinnervation during voluntary contraction, which were not seen before the treatment. However, fibrillation potentials at rest were still seen after the treatment. Patient 2: A 2-year-old girl was diagnosed with SMA type I at 6 months of age. She had received nusinersen two times and OA was administered at 7 months of age. The CMAP amplitudes and the MUPs presented similar changes as presented in Case 1.ConclusionThis is the first report on the changes in needle EMG findings after treatment in patients with SMA type I. These findings suggested that peripheral nerve reinnervation occurred after the treatment, although active denervation was still present. The accumulation of these findings will be important for evaluating the effectiveness of treatment for SMA in the future.

Menstrual Cycle Associated Alteration of Vastus Lateralis Motor Unit Function

BackgroundEstrogen and progesterone are the primary female sex hormones and have net excitatory and inhibitory effects, respectively, on neuronal function. Fluctuating concentrations across the menstrual cycle has led to several lines of research in relation to neuromuscular function and performance; however evidence from animal and cell culture models has yet to be demonstrated in human motor units coupled with quantification of circulating hormones. Intramuscular electromyography was used to record motor unit potentials and corresponding motor unit potential trains from the vastus lateralis of nine eumenorrheic females during the early follicular, ovulation and mid luteal phases of the menstrual cycle, alongside assessments of neuromuscular performance. Multi-level regression models were applied to explore effects of time and of contraction level. Statistical significance was accepted as p < 0.05.ResultsKnee extensor maximum voluntary contraction, jump power, force steadiness, and balance did not differ across the menstrual phases (all p > 0.4). Firing rate of low threshold motor units (10% maximum voluntary contraction) was lower during the ovulation and mid luteal phases (β = − 0.82 Hz, p < 0.001), with no difference in motor unit potentials analysed from 25% maximum voluntary contraction contractions. Motor unit potentials were more complex during ovulation and mid luteal phase (p < 0.03), with no change in neuromuscular junction transmission instability (p > 0.3).ConclusionsAssessments of neuromuscular performance did not differ across the menstrual cycle. The suppression of low threshold motor unit firing rate during periods of increased progesterone may suggest a potential inhibitory effect and an alteration of recruitment strategy; however this had no discernible effect on performance. These findings highlight contraction level-dependent modulation of vastus lateralis motor unit function over the eumenorrheic cycle, occurring independently of measures of performance.

Association of Complex Repetitive Discharges With Chronicity and Clinical Symptoms in Radiculopathies.

Complex repetitive discharges (CRDs) are incompletely understood needle electromyography (EMG) waveforms seen in both myopathic and neurogenic disorders including radiculopathies. This study aimed to clarify the significance of CRDs in patients with radiculopathies. This case-control study randomly identified 100 patients with needle EMG evidence of radiculopathy demonstrating at least one CRD in the electrodiagnostically involved myotome between January 2017 and January 2022. These patients were compared with 100 randomly selected patients with EMG evidence of radiculopathy without CRDs controlled for sex, age at EMG testing, and affected nerve root segment. Patient clinical symptoms, neurologic examination, EMG features, and imaging were analyzed. A paired sample t-test for categorial data and χ2 test for nonparametric data were used for statistical analysis with significance defined as P < 0.05. Patients with radiculopathies with CRDs had longer disease duration averaging 59 months (range 1-480) compared with patients with radiculopathies without CRDs averaging 26 months (range 1-192, P < 0.01). Clinical symptoms of paresthesias and weakness were both significantly more common in patients with radiculopathies with CRDs than those without CRDs (P < 0.01 and 0.01, respectively). Needle EMG demonstrated a greater average number of muscles with neurogenic motor unit potentials per radiculopathy in patients with radiculopathies with CRDs compared with those without CRDs. Imaging studies of patients with radiculopathies with CRDs were more likely to reveal evidence of nerve root compression (P < 0.01). The presence of CRDs in patients with radiculopathies is consistent with clinically more symptomatic radiculopathies and a longer duration of nerve root compromise.

Homozygous Mutations in GDAP1 and MFN2 Genes Resulted in Autosomal Recessive Forms of Charcot-Marie-Tooth Disease in Consanguineous Pakistani Families.

Charcot-Marie-Tooth disease (CMT) is a heritable neurodegenerative disease of peripheral nervous system diseases in which more than 100 genes and their mutations are associated. Two consanguineous families Dera Ghazi Khan (PAK-CMT1-DG KHAN) and Layyah (PAK-CMT2-LAYYAH) with multiple CMT-affected subjects were enrolled from Punjab province in Pakistan. Basic epidemiological data were collected for the subjects. Nerve conduction study (NCS) and electromyography (EMG) were performed for the patients. Whole-exome sequencing (WES) followed by Sanger sequencing was applied to report the genetic basic of CMT. The NCS findings revealed that sensory and motor nerve conduction velocities for both families were <38 m/s. EMG presented denervation, neuropathic motor unit potential, and reduced interference pattern of peripheral nerves. WES identified that a novel nonsense mutation (c. 226 G>T) in GADP1 gene and a previously known missense mutation in MFN2 gene (c. 334 G>A) cause CMT4A (Charcot-Marie-Tooth disease type 4A) in the PAK-CMT1-DG KHAN family and CMT2A (Charcot-Marie-Tooth disease type 2A) in the PAK-CMT2-LAYYAH family, respectively. Mutations followed Mendelian pattern with autosomal recessive mode of inheritance. Multiple sequence alignment by Clustal Omega indicated that mutation-containing domain in both genes is highly conserved, and in situ analysis revealed that both mutations are likely to be pathogenic. We reported that a novel nonsense mutation and a previously known missense mutation in GAPD1 gene and MFN2 gene, respectively, cause CMT in consanguineous Pakistani families.

Value of paraspinal muscle myography in diagnosing L5 radiculopathy

Introduction. Electromyography (EMG) is an important diagnostic tool for the evaluation of radiculopathy. Since 1990s a paraspinal mapping technique is used, which detects spontaneous activity in paraspinal muscles (PM) at the level of several vertebral segments. This modality seems to be highly conclusive for diagnosing radicular lesions. The main limitation of this method is spontaneous activity dependence on the disease duration.&#x0D; The aim of the study is to assess if PM EMG with motor unit potential (MUP) analysis is conclusive for diagnosing lumbar radiculopathy.&#x0D; Materials and methods. The study examined 58 patients (26 men and 32 women) aged 2673 years with MRI-confirmed symptomatic L5 mono-radiculopathy due to L4L5 herniated discs. The study assessed the neurological status and needle EMG of m. tensor fasciae latae (TFL) and PM at L4L5 and L3L4 levels on both symptomatic and healthy sides immediately before radicular microscopic decompression surgery. Surgery outcomes were evaluated by early and late postoperative questioning.&#x0D; Results. In PMs of the affected level and side, the average MUP duration was significantly different from opposite MUPs at the higher segment (р 0.001). At 3-month disease duration, a neurogenic pattern was significantly more frequent in affected PMs (p = 0.031) with neurogenic PM MUP rearrangement in 73.3% of patients. In the TFL (L5), neurogenic changes were reported only in 47.4% of patients. When compared to normal values, significant differences were found in the average duration of TFL MUPs (р = 0.001) and PM MUPs of the affected level and side (р 0.001) both in patients with motor disorders and those with isolated pain syndrome or sensory disorders.&#x0D; Conclusions. For diagnosing radiculopathy, the sensitivity of needle PM EMG is 82.6% (48/58; 95% CI 70.691.4%). Compared to limb myotome assessment, the highest informative value of PM EMG was reported in patients with the disease duration for up to 3 months. PM EMG was conclusive for diagnosing radicular lesions in patients with isolated pain syndrome or sensory disorders.